1. Field of the Invention
The present invention relates to a method of forming a color filter layer, and more particularly, to a method of forming a color filter layer having a rough surface that can provide light-scattering effect.
2. Description of the Prior Art
Liquid crystal display (LCD) panels are widely used as displays in electronic devices such as portable computers, PDAs, cell phones and flat TVs. Liquid crystal display panels can be simply classified into two types. One is transmissive type, and the other is reflective type. The former utilizes backlight as the light source and the latter utilizes ambient light. It is difficult to decrease the power consumption for the transmissive LCD due to the power requirements of the backlight. As for the reflective LCD, it has the advantage of power saving under bright ambient light; unfortunately, it cannot show images under dark ambient light.
In order to overcome the drawbacks of these two types of LCDs, a transflective LCD is disclosed. The transflective LCD can show images in not only transmissive mode but also reflective mode. Under bright ambient light, the backlight can be turned off, so the power consumption of the transflective LCD is lower than that of the transmissive LCD. In addition, under dark ambient light, the backlight can be turned on, so the image quality of the transflective LCD is better than that of the reflective LCD.
Please refer to FIG. 1. FIG. 1 is a sectional view of a conventional transflective LCD panel. As shown in FIG. 1, the conventional transflective LCD panel 10 includes a lower substrate 20 (also referred to as an array substrate), an upper substrate 30 (also referred to as a CF substrate), and a liquid crystal layer 40 interposed between the lower substrate 20 and the upper substrate 30. The transflective LCD panel 10 includes a plurality of pixel region 22, and each pixel region 22 can be divided in a reflection region 221 and a transmission region 222. The upper substrate 30 includes a plurality of color filters 32 corresponding to the pixel regions 22, and black matrices 34 disposed between the color filters 32.
The lower substrate 20 further includes a plurality of reflection electrodes 24 disposed in the reflection region 221, and a plurality of transmission electrodes 28 formed in the transmission region 222. In the reflection regions 221, each reflection electrode 24 is disposed on a bump structure 26 having a rough surface. The bump structure 26 renders the reflection electrode 24 a rough surface and this rough surface can provide a light-scattering effect on incident ambient light beams.
The conventional transflective LCD panel 10, however, suffers from some disadvantages. First, the color filters 32 are disposed on the upper substrate 30, and therefore cannot be perfectly aligned to the pixel regions 22 of the lower substrate 20. This causes reduction of aperture ratio of the conventional transflective LCD panel 10. In addition, one of the functions of the bump structure 26 is to form the rough surface of the reflection electrode 24. However, the bump structure 26 having a rough surface requires at least two patterning steps. One step is for forming the bump structure 26 in each reflection region 221, and the other step is for forming the rough surface. Therefore, the manufacturing cost is increased.